A parallax obtained from a stereoscopic image formed by right and left images corresponds to a depth from a user who views the stereoscopic image to a subject. Therefore, parallax detection of a stereoscopic image can be applied to various kinds of application software such as parallax adjustment or viewpoint synthesis of a stereoscopic image and a three-dimensional interface. The parallax detection of a stereoscopic image is associated with a problem of detecting corresponding points in right and left images (for example, see Japanese Unexamined Patent Application Publication No. 2009-008539).